Yarn processing systems, e.g. including a weaving machine and yarn feeding devices, contain accessory devices along the yarn path from the yarn supply up to, in some cases, the exit side of the weaving shed. The accessory devices serve to control, treat, monitor, scan, convey, etc. the yarn. At least some accessory devices have a signal transmitting connection to the control device of the yarn feeding device in order to transmit return messages or commands or to carry out adjustments of functional parameters. This needs considerable cabling equipment, representing acute error sources, and requires a sophisticated equipment and adaptation of the communicating components. Furthermore, yarn processing systems are known (weaving machine including yarn feeding devices and accessory devices), which are equipped with a rapid communication main bus system for serial data transmission via which e.g. a superimposed control device or the control device of the weaving machine, respectively, communicates with the yarn feeding devices and, in some cases, with the accessory devices. Even information of the speed or the rotational angle of the textile machine and/or of the drive of the yarn feeding device may be transmitted in some cases via the main bus system. Since during operation of the yarn processing system a plurality of data of frequently differing priorities is to be transmitted, and since modern yarn processing systems are extremely complex, the integration also of accessory devices may overwhelm the capability of the main bus system, or the communication with the accessory device may suffer from the dominance of higher ranking communications. The intelligence of the main bus system useable for the accessory devices is limited, e.g. if the main bus system has to interlink a plurality of yarn feeding devices and accessory devices and a jacquard weaving machine. The communication via the main bus system needs a sophisticated and costly equipment of the accessory devices. The volume of data which is to be transmitted may be too large for the main bus system in some cases.
It is the object of the invention to provide a yarn processing system of the kind as disclosed at the beginning as well as a yarn feeding device for such a yarn processing system, with which the above-mentioned drawbacks are avoided and for which unintentionally customised intelligence is useable for the communication with accessory devices.
In the local bus system only accessory devices will communicate at least with the control device of the yarn feeding device which accessory devices are connected to the local bus system. Superimposed or higher ranking communications do not interfere with or limit the accessory device data exchange. The local bus system is adapted with reduced efforts for the functions which are to be carried out by the accessory devices and is designed with an intelligence intentionally coping with the accessory devices and allowing an optimum yarn control, yarn monitoring or yarn treatment, respectively. A serial data transmission within the local bus systems allows to achieve sufficient quickness and reliability. The autonomic design of the local bus system makes the bus system independent from in some cases superimposed communications of the yarn feeding device within a main bus system. In some cases the yarn feeding device may operate independent from the textile machine even only depending on the yarn consumption to which the yarn feeding device with the accessory devices within the local bus system is reacting itself by monitoring and controlling actions.
Expediently, the local bus system is customised for the communication with the accessory devices and may, e.g., for that reason be simpler in terms of the cabling equipment, even if the accessory devices may have a fair cost equipment which would not be directly compatible with a main bus system. This allows to save costs. Furthermore, at any time accessory devices may be added or removed, since the local bus system is very flexible.
The yarn feeding device with its local bus system for the accessory devices is capable to optimally adapt to the operation conditions and to communicate with the accessory devices on a high level of operational safety. The control device of the yarn feeding device is informed about the actions in and at the accessory devices, is apt to precisely control, adjust, activate or de-active the accessory devices. Thanks to a serial data transmission even complex data may be transmitted rapidly and reliably. The local bus system may be designed in a flexible fashion such that an unlimited number of accessory devices of different kinds may be connected to or removed without interference with superimposed data transmission processes in a main bus system which may be provided in some cases. Normally, two conductors suffice for the local bus system, in some cases even a connection having only one conductor. Respective interface processors or simple microcontrollers or PC-boards allow a simple equipment of the accessory devices and within the local bus system.
In a premium communication system each feeding device of the yarn processing system is a node of a rapid communication main bus system via which the yarn feeding devices communicate with each other or with a superimposed control device and/or a control device of the textile machine, via which they receive commands or information or supply return messages. Another kind of data transmission may take place in the main bus system than in the local bus system. It is, however, possible to choose at least similar data transmission kinds in the main bus system and in the local bus system in order to e.g. selectively carry out also an indirect communication from the main bus system to a local bus system, or vice versa. The local bus system of the yarn feeding device provided for the connected accessory devices may be a complementary sub-system for the main bus system.
As the requirements in terms of operation, monitoring or adjustment of accessory devices normally are lower than for the communication between the textile machine and the yarn feeding devices a local bus system may be expedient which is slower in comparison to a rapid main bus system, because then the cabling equipment and the costs for the electronic equipment may be reduced. Such a rapid main bus system e.g. may be a CAN-bus system operating with a bit transmission rate larger than 20 kbps while the slower local bus system only needs to be designed for a bit transmission rate of less than 20 kbps (kilobytes per second). Expediently, the local bus system is a single conductor sub-system being complementary with the rapid main bus system. The sub-system may be based on a UART-standard-equipment of the control of the yarn feeding device (universal asynchronous receiver and transmitter). The reason is that UART-connections are by far the simplest prerequisite for implementing a serial communication. Such UART-connections already are present in the form of on-chip-periphery equipment in virtually all modern microcontrollers. Within the UART-standard messages are transferred in the form of bytes-level-characters. By completion with some external, simple driving circuitries and by interlinking two UART-connections a simple single conductor connection may be achieved (in connection with a logic ground connector). The single conductor connection is connected in wired-or-configuration and allows a bi-directional half duplex-communication. Messages are emitted by the bus master in the form of frames. The specification of the frame defines a simple identifier by which e.g. 60 differently defined messages may be formed. Fair costs low-end microcontrollers may be connected to the single conductor connection on the UART-standard base, i.e., the requirements for the hardware are only low such that totally a fair cost but function safe local bus system can be achieved.
The local bus system based on the UART-standard only needs a single conductor connection of two UART-connections to at least one microcontroller of the accessory device, or via an accessory device-PC board, which in some cases may be completed by an external driving circuit.
In case that such a simple local bus system is used for a relatively slow transmissions of adjustment values, target values, on/off commands, filter adjustments, schemes of modulation, and the like, the local bus system expediently may be completed by at least one separate SYNC-line for the real-time transmission of information representing either the textile machine rotational angle or the textile machine position or the rotational angle or the position of the drive of the yarn feeding device or the respective speeds, respectively. By the common consideration of the communication within the local bus system and of the information given in the separate SYNC-line the accessory devices are apt in a flexible fashion to operate very precisely. Such a local bus system then is upgraded to be substantially of equal value as to a rapid main bus system extending to the accessory devices, which however is by far more costly.
Expediently, accessory devices located at the entrance side of the yarn feeding device, are connected to a SYNC-line which transmits as an information for the operation of the accessory device the speed or the rotational angle or the position of the drive of the yarn feeding device, while accessory devices located at the exit side of the yarn feeding device are connected to a SYNC-line reporting the speed or the rotational angle or the position of the textile machine, respectively. Also in this case the combination of a simple local bus system and of the SYNC-lines results in relatively high intelligence useful for the operation of the accessory devices. A pulse chain which is proportional to the speed, e.g. may be transmitted on the SYNC-line. The accessory device may then combine that information with the content of the communication within the local bus system without using e.g. the control device of the textile machine or the main bus system, respectively.
Alternatively, the sensor and/or the drive motor and/or parameter adjustment assemblies and/or yarn control assemblies of the feeding device itself may be connected additionally to the local bus system.
In case of demand local bus systems of several yarn feeding devices may be interconnected at least selectively for a lateral communication. Then data may be transmitted from one local bus system into another local bus system, expediently under surveillance by the control device of a yarn feeding device which control device then is functioning as a master. It is possible to allow a direct intercommunication between accessory devices, e.g. for transmitting or recalling functional parameters which are valid for several equal accessory device within the yarn processing system. Basically, it may be expedient to separate the local bus systems from the rapid main bus system e.g. by the control device of the respective yarn feeding device.
In an alternative solution a selectively activated interface may be provided between the main bus system and at least one local bus system, e.g. in or at the control device of the respective yarn feeding device.
It is not necessary to base the local bus system on the UART-standard. Alternatively, the local bus system may be a CAN-bus system or a daisy chain bus system for serial data transmissions. In such cases, however, the high costs for each node in a local CAN-bus are only justified if accessory devices are connected which have extremely valuable equipment and functionality.
Each accessory device, expediently, is connected via at least one interface processor or a accessory PC board, respectively, to the yarn feeding device control device, or is connected to a yarn feeding device main PC board of the yarn feeding device control device. These designs simplify to exchange, remove or add accessory devices.
The node of a yarn feeding device in the main bus system expediently ought to comprise a cluster which connected to the main bus system via a general power supply.
Accessory devices connected to a local bus system of a yarn feeding device may be different natures. An accessory device at the entrance side of the yarn feeding device e.g. could be an electronic yarn run sensor and/or yarn breakage sensor, and/or yarn speed sensor, and/or yarn quality sensor which not only delivers signals into the local bus system but also may be adjusted in terms of its functional parameters. The accessory device receives the required information on the speed or the rotary angle e.g. via the SYNC-line incorporated into the local bus system. An accessory device at the entrance side of the yarn feeding device may be a yarn oiler or a yarn waxer treating the yarn with an impregnation agent such that the application of the impregnation agent is variable via the local bus system, that the function is monitored and in some cases information is exchanged on the filling level or the amount of the stored impregnating agent. Another accessory device at the entrance side could be a slip conveyor operating in dependence from the speed of the drive of the yarn feeding device and which needs to be adjusted to the speed. An accessory device at the exit side of the yarn feeding device may be a controlled yarn brake the braking effect of which needs to be varied, activated or de-activated during the yarns runs with the help of information transmitted in the local bus system. In this case also the speed or rotational angle information from the textile machine may be used in some cases by means of the SYNC-line. In the local bus system also a function monitoring or the like can be carried out. A further accessory device located at the exit side of the yarn feeding device may be a tensiometer for scanning or reporting the yarn tension. If needed, in such a case the tensiometer may be supplied with speed information via the SYNC-line, while measured values and functional parameters are transmitted in the local bus system. The measured values, e.g. may be used for controlling a yarn brake, e.g. by means of the local bus system. The operation or sensitivity of the tensiometer may be monitored or adjusted. The tensiometer may in some cases be integrated into or interlinked with a controlled yarn brake. A further accessory device at the exit side of the yarn feeding device is a weft yarn detector reporting in dependency from the speed or the rotational angle of the textile machine the yarn running motion or the yarn stop, and which emits in case of a disturbance a disturbance signal and which may be adjusted e.g. in terms of its sensitivity or may be calibrated, respectively, via the local bus system. An accessory device at the exit side of the yarn feeding device and in the local bus system even may be a variable slip conveyor. Furthermore, a pneumatic threading device or a pneumatic yarn removing device, which e.g. is activated or de-activated by means of solenoid valves and is surveyed in view to the operation, could be provided as an accessory device, or even a pneumatic yarn stretcher. Functional parameters for these accessory devices are transmitted in the local bus system, while the speed and rotation angle information is provide via at least one SYNC-line.